Hiya, I noticed something pretty annoying today on our TF2 servers.. Even though -tickrate was set to 33 anyone with a cl_cmdrate of 66 and cl_updaterate of 66 was able to send/receive the full 66 tickrate, it wasn't until I limited sv_maxcmdrate and sv_maxuploadrate that it was limited to 33..

The tickrate is the main setting for the updates/second. Limiting this to the clients with a cvar like sv_maxupdaterate 33 will bring down the bandwidth usage but it will also bring choke up since the server actually wants to broadcast at 66 ticks per second.
That's why the tickrate command should work because it will keep using the same CPU if it stays at 66 tick regardless of limiting the clients to 33 tick.